Solution for: Custom post type single/page returns 404 error

So you have been stuck with the error 404 on your custom post type singles or pages? Google returns no functional answer?

Here is the solution.
Log in tom your WordPress, go to your Settings > Permalinks and set the permalinks to this:

/%post_id%/%postname%/

This way the WordPress will recognize the custom post types better plus the rewrite rules takes less time to resolve.